The invention relates to sensors and methods for analyte detection, and more particularly to sensors and methods for chemical and biological sensing applications.
An appropriate selection of sensing material is one of the aspects in sensor performance and application. The key performance indicators for sensors are selectivity, sensitivity and reliability.
Selectivity is the ability of the sensor to respond only to a specific analyte or a group of analytes. High sensor selectivity is required to detect trace concentrations of analytes in the presence of other contaminants, which result in high background levels of interference. Currently known sensors do not exhibit high selectivity under such conditions.
Sensitivity of a sensor is the output produced per unit change in concentration of an analyte. Stability of the sensor sensitivity and selectivity are also important factors. This stability of sensitivity and selectivity of the sensor is known as reliability.
Impedance spectroscopy is a standard technique currently used to characterize fundamental aspects of material performance. In impedance spectroscopy, a sensing material is positioned between electrodes and is probed over a wide frequency range (from a fraction of Hz to tens of MHz) to extract the fundamental information about dielectric properties of the material and vapor effects on these properties. But applicability of impedance spectroscopy in practical sensors for detection of trace levels of analytes is limited due to its low sensitivity in reported measurement configurations and prohibitively long acquisition times over the broad frequency range.
Therefore, there is a need for sensing materials in combination with a proper transducer to achieve high levels of sensitivity, selectivity and reliability for identifying analytes.